Effects of interleukin 11 (IL-11) on early post-implantation development of the rat

Implantation and immunology: maternal inflammatory and immune cellular responses to implantation and trophoblast invasion

Implantation and placentation present an immune challenge because of the semi-allogeneic nature of the conceptus. In this review, histological evidence for maternal immune cellular responses at the implantation site is summarized. Decidualization of the endometrium itself has features in common with an inflammatory response. During decidualization, infiltration by uterine natural killer (NK) cells occurs, and these interact with the non-polymorphic human leukocyte antigen (HLA) class I antigens expressed by invading extravillous trophoblasts. In humans, extension of trophoblast invasion beyond the decidual layer into the myometrium presents an additional challenge, which might be relevant for pregnancy complications such as pre-eclampsia. How far maternal cellular responses to invading trophoblasts seen at later stages of pregnancy can be traced back to the implantation period is an open question.

Differential effects of IL-11 on rat blastocysts and decidua during the peri-implantation period

PROBLEM

To study effects of interleukin-11 (IL-11) on blastocyst development and decidualization.

METHOD OF STUDY

Rats, injected with buffer (C) or IL-11 [1 mg/kg/day = high dose (HD), 60 microg/kg/week = low dose (LD)-1, 30 microg/kg twice a week = low dose (LD)-2] were made pregnant or pseudopregnant to obtain blastocysts or deciduomata.

RESULTS

As compared with C, more LD-2 blastocysts hatched in culture, while hatching and attachment of HD blastocysts was decreased. Blastocysts from untreated rats in IL-11 supplemented medium (4 ng/mL) demonstrated increased hatching and attachment. The weight of the decidualized uterus in HD and LD-2 pseudopregnant rats was reduced as compared with C and LD- 1. On deciduomata sections from IL-11 treated rats, the area inside the uterine muscle layer was reduced, and mitotic over pycnotic indices were increased in the anti-mesometrial area and decreased in the mesometrial area.

CONCLUSIONS

Low doses of IL-11 improve hatching and attachment of blastocysts, but both high and low doses impair decidualization.

Localization of pro-inflammatory (IL-12, IL-15) and anti-inflammatory (IL-11, IL-13) cytokines at the foetomaternal interface during murine pregnancy

The involvement of some interleukins (ILs) in early and established pregnancy has been convincingly demonstrated, but little is known about the potential role of the more recently discovered ones. However, since many of these have positive or negative regulatory effects on both NK and T cells, it is highly probable that they also have regulatory functions in both implantation and placental development. Therefore, as a first step in tackling this problem, we have investigated whether several recently described pro- (IL-12, IL-15) and anti-inflammatory (IL-11, IL-13) cytokines were expressed at the uteroplacental interface by use of immunohistochemistry at different stages of gestation in mice. Each of these molecules was found at the foetomaternal interface, with specific distributions and patterns of expression depending on both the cytokine itself and the stage of pregnancy. The significance of these data is discussed.